The present invention relates to a method of increasing the fatigue strength of crankshafts for reciprocating engines, especially internal combustion engines, and includes the step of subjecting the transition radii from a crankshaft pin to adjacent crank webs to a special treatment.
Increasing the power of internal combustion engines is achieved via supercharging, which results in an increase of the mechanical forces in the overall piston drive. At the same time, in order to reduce costs for various engine models, it is desirable to avoid retooling and recalculation of components to the greatest extent possible.
For this purpose, it is attempted to increase the fatigue strength of components by improving the quality of the surface. Pursuant to known strength of material principles, the fatigue strength of a component can be increased by fine burnishing and polishing of the surface, and hence a reduction of the peak-to-valley height, i.e. the micro scoring. However, fine burnishing and polishing of the surface is relatively cost intensive.
It is therefore an object of the present invention to increase the fatigue strength of crankshafts in the region of the transition from the crankshaft pin to the crank web without altering the geometry and without expensive machining or finishing of the surface.